But when one of Microsoft's letters seeking repayment surfaced on the Web on Saturday, the situation turned embarrassing. On Monday, the company reversed course and said the laid-off workers could keep the extra payouts.

Lisa Brummel, Microsoft's senior vice president for human resources, said the letters were mailed to 25 of the 1,400 people let go in January. Most of the checks were off by about $4,000 to $5,000, she said.

Brummel said she learned of the letters over the weekend after one appeared on the technology blog TechCrunch.

"I decided it didn't quite feel right," she said in an interview.

The executive called most of the 25 laid-off employees Monday to personally tell them Microsoft would not seek repayment after all.

Redmond, Washington-based Microsoft also gave about 20 employees too little severance. When the company noticed its mistake, it sent checks and explanations to those people, she said.

Brummel called the glitch a clerical error, and said that at some point in the process of calculating severance packages, communicating with employees and cutting checks, "we had payments misaligned with people's names." (Brummel said she didn't know whether an Excel spreadsheet was at the root of the problem.)

With the recession biting into sales of Microsoft's core Office and Windows software, the company said in January it would let up to 5,000 of its 94,000 employees go, the only mass layoff in its 34-year history. Microsoft remains profitable, however, and has a cash hoard of nearly $21 billion.

Shares of Microsoft sank 79 cents, or 4.4 percent, to close at $17.21.

No word yet on whether the laid-off microserfs who did not receive extra severance will be rewarded like their brethren.